Connect Jetson nano to arduino nano over i2c communication
Table of Content
Connect Jetson nano to arduino nano over i2c communication#
Connect jetson nano to arduino nano via i2c Install linux i2c tools and check communication with smbus python library
wiring#
| arduino | jetson |
|---|---|
| GND | GND |
| A4(SDA) (23) | 27(SDA) |
| A5(SCL) (24) | 28(CLK) |
Pinouts#
Jetson gpio pinout#
Arduino nano pinout#
Arduino nano#
Nano usb disconnect from ttyUSB
dmesg output
[1182096.667353] usb 1-9: ch341-uart converter now attached to ttyUSB0
[1182096.729868] audit: type=1130 audit(1637925474.011:3648): pid=1 uid=0 auid=4294967295 ses=4294967295 msg='unit=brltty-device@sys-devices-pci0000:00-0000:00:14.0-usb1-1\x2d9 comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
[1182096.800144] audit: type=1130 audit(1637925474.081:3649): pid=1 uid=0 auid=4294967295 ses=4294967295 msg='unit=brltty@-sys-devices-pci0000:00-0000:00:14.0-usb1-1\x2d9 comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
[1182096.803145] usb 1-9: usbfs: interface 0 claimed by ch341 while 'brltty' sets config #1
[1182096.803731] ch341-uart ttyUSB0: ch341-uart converter now disconnected from ttyUSB0
Remove ubuntu 22.04 support to braille e-reader
sudo apt remove brltty
Nano avrdude: stk500_getsync()
Switch to old bootloader
Tools > Board > ATmega328P (Old Bootloader)
Code example#
#include <Wire.h>
int i2cAddress = 0x40;
int servoState = 0;
int data = 0;
void setup()
{
Wire.begin(i2cAddress); // join i2c bus with address #0x40
Wire.onReceive(receiveEvent); // register event
Wire.onRequest(sendData);
Serial.begin(9600); // start serial for output
Serial.println("hello i2c");
}
void loop()
{
if(servoState > 0) {
data = servoState;
servoState = 0;
Serial.println(data);
}
}
void receiveEvent(int bytes) {
servoState = Wire.read(); // read one character from the I2C
}
void sendData(){
Wire.write(data);
}
jetson#
dependencies
sudo apt-get install i2c-tools
sudo pip install smbus
Check and test using CLI#
sudo i2cdetect -y -r 0
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: 40 -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --
Test#
- Upload application to Arduino
# sudo i2cset -y <bus number> <address> <data>
sudo i2cset -y 0 0x40 0x10
Python code#
import smbus
# Nvidia Jetson Nano i2c Bus 0
bus = smbus.SMBus(0)
# This is the address we setup in the Arduino Program
address = 0x40
def writeNumber(value):
bus.write_byte(address, value)
def readNumber():
number = bus.read_byte(address)
return number
while True:
var = input("")
if not var:
continue
writeNumber(int(var))
number = readNumber()
print(f"--{number}--")
Run i2c as non-root user#
check permission
ll /dev/i2c*
crw-rw---- 1 root i2c 89, 0 Oct 4 09:30 /dev/i2c-0
crw-rw---- 1 root i2c 89, 1 Oct 4 09:30 /dev/i2c-1
bash title="add user 2 i2c group
sudo usermod -aG i2c ${USER}